body {
    margin: 0;
	 background-image: url("../img/beijing.bmp");
}

#all_body{
    margin: 0 auto;
    width: 1024px;
    height: 768px;
    background-image:url(../img/bgcolor.jpg);
}
#middle_body{
    margin: inherit;
    float: left;
    position: absolute;
}
